NeoST

Atari Mega STE in your browser · WebAssembly · cycle-exact Moira 68000 · EmuTOS

Loading the WebAssembly module… —

Machine

Load local ROM…

Floppies

Load local floppy… or drop a floppy / ROM on the screen

Save states

Load state…

Display & peripherals

Volume 80 %

Keyboard opacity 50 %

Mouse opacity 50 %

Joystick

Dead zone 0.30

Joystick opacity 50 %

Button count

Touch buttons

Help & shortcuts

Mouse: click the middle button (usually the wheel), or press Ctrl+Alt+G, to capture or release it (GEM cursor). Esc and Del are sent to the ST.
Touch mouse: enable it in Display & peripherals, then drag one finger on the screen to move the GEM mouse. Double-tap for a left click; the left and right mouse buttons also appear below the screen. It is off by default so the page can still scroll normally.
ST keyboard: enable the on-screen keyboard in Display & peripherals, or use Display keyboard in full screen. Keys are sent directly to the Atari IKBD; Shift remains active for the next key.
Keyboard: routed to the IKBD (US layout). Keyboard joystick: arrows + right Ctrl = fire, on the port picked in the Joystick box (port 1 by default).
Touch joystick: enable the floating eight-direction pad and four action buttons on joystick port 1. Assign A/B to common actions, or X/Y to any Atari ST keyboard key in the Joystick controls.
Bluetooth & USB controllers: pair or connect the controller with your device, then press any controller button once in this page. The first controller is assigned to joystick port 1 and the second to port 0. The dead zone slider only affects analog sticks, not the D-pad.
Reset: a cold reset (power-cycle) — ST-RAM is wiped and TOS boots from scratch, which is also what mounting a floppy in A: does.
Game floppies: "Mount A: + Reset" switches to a real TOS when one is available (EmuTOS boots system floppies only) — TOS 2.06 on STE/Mega STE, TOS 1.0x on ST. This build bundles EmuTOS alone, which is free software; original Atari TOS ROMs are not ours to ship. Most commercial games therefore need you to add one to /roms and pick it above. The bundled demos boot fine on EmuTOS.
Save states: Save state downloads a .state file to your browser's Downloads folder. Use Load state… to restore it with the same machine, RAM size, and ROM.
Drag and drop: drop a .st / .msa / .dim / .stx image straight onto the screen to mount it in A: and reboot. Drop a .img / .rom / .tos / .bin file to load it as the ROM instead; it stays only in this browser tab.
Machine & RAM: fixed when the machine is built → changing them reloads the page (URL parameters ?machine= and ?mem=, shareable).
Sound: browsers require a user gesture — click once inside the screen to unlock audio (YM2149 + STE DMA + drive noises).